Migrate HostZoomMap to live in StoragePartition.

content/shell/browser/shell_browser_context.cc

Index: content/shell/browser/shell_browser_context.cc
diff --git a/content/shell/browser/shell_browser_context.cc b/content/shell/browser/shell_browser_context.cc
index 8a97911c349c86f4211bd4b7d7bcf762e594918f..9f835624181515958f9d46f7292938822e79760c 100644
--- a/content/shell/browser/shell_browser_context.cc
+++ b/content/shell/browser/shell_browser_context.cc
@@ -95,6 +95,11 @@ void ShellBrowserContext::InitWhileIOAllowed() {
     base::CreateDirectory(path_);
 }
 
+scoped_ptr<ZoomLevelDelegate> ShellBrowserContext::CreateZoomLevelDelegate(
+    const base::FilePath&) {
+  return scoped_ptr<ZoomLevelDelegate>();
+}
+
 base::FilePath ShellBrowserContext::GetPath() const {
   return path_;
 }